Polychloroprene-free wetsuit and material

ABSTRACT

A polychloroprene-free wetsuit and material is described consisting of a class of copolymers or a physical mix of polymers consisting of materials with both thermoplastic and elastomeric properties to produce thermoplastic resin pellets. The non-toxic thermoplastic resin pellets are mixed with additives and a blowing agent to produce thermoplastic elastomer closed-cell foam for use in wetsuits. Depending on the wetsuit application, the density of the thermoplastic elastomer foam may vary. In many wetsuit applications low densities such as less than 0.25 grams/cubic centimeters are desirable.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/564,875 filed on Aug. 2, 2012, Entitled,“Polychloroprene-free Wetsuit and Material,” the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND

This disclosure relates generally to polychloroprene-free materialshaving qualities for use in wetsuits and other products. In particular,this document describes thermoplastic elastomer closed-cell foammaterial.

Surfers, jet skiers, wake boarders, windsurfers, kayakers, whitewaterrafters, scuba divers, snorkelers, and fishermen use wetsuits forthermal insulation, comfort and protection during water recreation.Essentially, wetsuits are a form of thermal covering that traps a thinlayer of water against the wearer's skin. The thin layer of watercombined with an insulating material of the thermal covering allows bothto be warmed by body heat.

The insulating material commonly used for wetsuits is polychloroprene,also known as neoprene, a product of synthetic rubber. Unfortunately,polychloroprene has several major disadvantages. These include rubberallergy, high toxicity, and a high carbon footprint, among others. Withregard to rubber allergy, 15% of the world's population is allergic topolychloroprene. The American Contact Dermatitis Society labeledneoprene rubber as a common source of mixed dialkyl thioureas, and in2009 labeled polychloroprene as “Allergen of the Year” as being aprimary source of allergic contact dermatitis. As for polychloroprene'stoxicity, the material contains heavy metals, formaldehyde, phthalates,lead, and chlorine, which are all known to be harmful to humans. Withregard to polychloroprene's carbon footprint, the material resistsdecomposition until temperature extremes of approximately 800 degreesCelsius, at which point it converts into carbon and omits toxic gas.Unfortunately, landfills and environmental decomposition conditionsdon't reach the temperature requirements to adequately decomposepolychloroprene. This effectively means that polychloroprene willeffectively not degrade over time. The process of decomposition isessential for recycling finite matter that occupies the physical spaceof this planet.

Thus, there exists a clear need for a wetsuit material that is not basedon polychloroprene, does not have the allergen potential or the levelsof toxicity of polychloroprene, and which has a lower carbon footprintin manufacturing and is more readily decomposable than polychloropreneand conventional materials suitable for such applications as wetsuits orthe like.

SUMMARY

This document describes a polychloroprene-free material for use in awetsuit and other products. In some aspects, the polychloroprene-freematerial is formed of thermoplastic elastomer closed-cell foam materialhaving a low density. In some instances, the density of the closed-cellfoam material can be less than 0.25 grams/cubic centimeter.

In some aspects, the thermoplastic elastomer material is based on anhypoallergenic thermoplastic elastomer closed-cell foam. Thethermoplastic elastomer material described herein insulates as well orbetter than polychloroprene. As used as a wetsuit material, thethermoplastic elastomer material can withstand tearing, rough handlingand severe conditions, yet is inherently flexible. Furthermore, thethermoplastic elastomer material is inert to most chemical agents, andis free of heavy metals, formaldehyde, phthalates, lead, and chlorine,or other toxic agents or compounds.

In one aspect, a wetsuit is disclosed. The wetsuit includes one or moresheets of closed-cell foam formed to cover one or more body parts of awearer. The closed-cell foam is derived from thermoplastic elastomermixed with at least one foaming agent, and being formed to a density ofless than 0.25 grams per cubic centimeter, each of the one or moresheets of closed-cell having a thickness between 2 millimeters and about5 millimeters and enabling movement of the one or more body parts of thewearer when covered by the one or more sheets of closed-cell foam.

In another aspect, a method for manufacturing a wetsuit is disclosed.The method includes providing one or more sheets of closed-cell foamformed to cover one or more body parts of a wearer. As described above,the closed-cell foam is derived from thermoplastic elastomer mixed withat least one foaming agent. The closed-cell foam is formed to a densityof less than 0.25 grams per cubic centimeter. Each of the one or moresheets of closed-cell have a thickness between about 2 millimeters andabout 5 millimeters and enabling movement of the one or more body partsof the wearer when covered by the one or more sheets of closed-cellfoam. The method further includes assembling the one or more sheets ofclosed-cell foam into a pattern defining at least a portion of thewetsuit.

The polychloroprene-free material can be used for many otherapplications, such as thermal insulation, bonding, covering,waterproofing, and the like. The details of one or more embodiments areset forth in the accompanying drawings and the description below. Otherfeatures and advantages will be apparent from the description anddrawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described in detail with referenceto the following drawings.

FIG. 1 is a cross section of the thermoplastic elastomer closed-cellfoam;

FIG. 2 is a cross section of the thermoplastic elastomer closed-cellfoam with a fabric covering;

FIG. 3 is a cross section of the thermoplastic elastomer closed-cellfoam with an inner liner;

FIG. 4 is a cross section of the thermoplastic elastomer closed-cellfoam with a fabric covering and an inner liner; and

FIG. 5 illustrates a wetsuit using thermoplastic elastomer closed-cellfoam.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

This document describes a polychloroprene-free material for use in awetsuit and other products. The polychloroprene-free material caninclude, without limitation, a hypoallergenic thermoplastic elastomerfoam, which can be formed to insulate as well as, or better than,polychloroprene (commonly known as neoprene). Further, thermoplasticelastomer foams as described herein withstand tearing, rough handlingand severe conditions, are inherently flexible, and can be formed to adesired flexibility and pliability. Thermoplastic elastomer foams areinert to most chemical agents, and are free of formaldehyde, phthalates,lead, chlorine, or other toxic agents or compounds.

In some implementations, the polychloroprene-free material is formed atleast in part of thermoplastic elastomer foam (TPE foam), and inspecific implementations, can be based on a hypoallergenic thermoplasticelastomer closed-cell foam, as described in further detail below.Thermoplastic elastomer closed-cell foam is a low modulus, flexiblematerial that can be stretched repeatedly, which is an idealcharacteristic for the production of material for wetsuits, footwear,accessories, bags, or the like.

Thermoplastic elastomers (TPEs) are a group of polymers that exhibitinstantaneous reversible deformation (to be an elastomer). Most TPEsconsist of a continuous phase that exhibit elastic behavior and adispersed phase that represents the physical crosslinks. If thedispersed phase is elastic, then the polymer is a toughenedthermoplastic, not an elastomer. Elastomer reversibility must havephysical cross-links, therefore these crosslinks must be reversible.Physical crosslinks do not exist permanently and may disappear with theincrease of temperature.

TPE foam is made up of a class of copolymers or a physical mix ofpolymers consisting of materials with both thermoplastic and elastomericproperties. Generally, thermoplastic elastomers can be categorized intotwo groups: multi-block copolymers and blends. The first group iscopolymers consist of soft elastomers and hard thermoplastic blocks,such as styrenic block copolymers (SBCs), polyamide/elastomer blockcopolymers (COPAs), polyether ester/elastomer block copolymers (COPEs)and polyurethane/elastomer block copolymers (TPUs). TPE blends can bedivided into polyolefin blends (TPOs) and dynamically vulcanized blends(TPVs).

In some implementations, as used herein, thermoplastic elastomers aretwo-phase systems consisting of a rubbery elastomeric (soft phase)component and a rigid (hard phase) component. The soft phase can includepolybutadiene, poly(ethylene-co-alkene), polyisobutylene,poly(oxyethylene), poly(ester), polysiloxane or any other elastomers,while the hard phase can include polystyrene, poly(methyl methacrylate),urethane, ionomer—poly(ethylene-co-acrylic acid) (sodium, Mg, Zn salt),ethylene propylene diene monomer, and fluropolymers.

Thermoplastic elastomers must be two-phase materials, and each moleculemust consist of two opposite types of structure, one the elastomericpart and the second the restraining, physical cross-linking part.Thermoplastic elastomers are typically block copolymers. The elasticblock should have high molar mass and possess all of the otherscharacteristic required of an elastomer. The restraining block shouldresist viscous flow and creep. One restraining block can be used permacromolecule, giving a diblock copolymer (AB), or one restraint blockat each of the elastomer can be used giving a triblock copolymer (ABA).To provide an example of thermoplastic elastomer block copolymerstructures the monomers butadiene and styrene are chosen.

TPE closed-cell foam that is suitable for the presently describedimplementations includes a thermoplastic elastomer (thermoplasticpolymer resin) compound, sometimes referred to as thermoplastic rubber.In some implementations, the thermoplastic elastomer (thermoplasticpolymer resin) compound is made up of a class of copolymers or aphysical mix of polymers that includes materials with both thermoplasticand elastomeric properties. The TPE foam used herein can have athermoplastic elastomer (thermoplastic polymer resin) content of between40% and 60%, but can also have an thermoplastic elastomer (thermoplasticpolymer resin) content of less than 40% and greater than 60%. Inparticular implementations, the TPE foam is formed with a foaming agent,and includes additives, and/or fillers. For example, a suitable foamingagent can be a chemical foaming and nucleating agent such as Hydrocerol®marketed by Clariant Corporation. Additives can include pigments, dyes,or thermal enhancement compounds. Fillers can include, for example,calcium carbonate to improve cell structure of the closed cell foam.Other foaming agents, additives, and/or suitable fillers can be used.

FIG. 1 illustrates a cross-section of an elastomer material 20 that ispolychloroprene-free, for use in wetsuits and other products. In someimplementations, the elastomer material 20 is made from thermoplasticelastomer closed-cell foam, 21. The thickness of the elastomer material20 may vary, depending on a specific application, such as where thewetsuit is used, for how long, etc. In some implementations, thethickness of the elastomer material 20 is sufficient to allow movementby the wearer, yet thermally insulative to protect the wearer.Accordingly, the elastomer material 20 can have thicknesses ofsubstantially two millimeters, three millimeters, four millimeters, ormore. In other implementations, the elastomer material 20 can have athickness of less than two millimeters. Thermoplastic elastomerclosed-cell foam may be produced in various colors to further enhancethe desirability of a wetsuit formed of the elastomer material 20.

A method of producing a thermoplastic elastomer closed-cell foamincludes providing a foamable thermoplastic elastomer (thermoplasticpolymer resin), such as Thermolast® by KRAIBURG TPE GmbH & Co. KG,having a suitable hardness value to permit production of soft,low-density foam. The provided foam preferably exhibits compressibility(i.e. load bearing) characteristics that allow the foam to deformeasily, yet still resist permanent deformation (compression set) whenthe load is removed. Other suitable thermoplastic elastomers(thermoplastic polymer resins) can be used.

In accordance with one method consistent with implementations describedherein, a thermoplastic elastomer closed-cell foam formed byincorporating polymerized thermoplastic resin compound pellets into amelted mixture with foaming agents, black carbon pigments, or,alternatively, other colored pigments, fillers, plasticizers, and otherdesired additives. The mixture of polymerized thermoplastic resincompound pellets, foaming agents and other fillers are then baked in anoven to expand the mixture into a foam block. Once baked, the foam blockis cooled, leaving a large closed-cell foam sponge block ofapproximately 150 mm thick with a very high independent closed-cellstructure. As soon as the sponge block is cured, it is then slicedhorizontally into foam sheets of a desired thickness.

In alternative implementations, a thermoplastic elastomer closed-cellfoam is produced by feeding polymerized thermoplastic resin compoundpellets into an extruder, and through the shearing action of one or morescrews, melting the compound continuously in the barrel of the extruder.In an intermediate or a mixing section, a blowing agent, usually in aliquid or gaseous state, is continuously injected into the moltencompound. In some instances, a chemical blowing agent can dispersedthroughout the particulate compound in a powder form before the materialis fed to the extruder. In either case, the extruder screw can bedesigned to mix and dissolve the blowing agent as uniformly as possiblein the molten compound. Thorough, uniform mixing is essential to theproduction of high quality foam. The resultant mixture is maintainedunder carefully controlled temperatures and pressures within theextruder in order to prevent the volatilization of the blowing agent.

The molten mixture is then forced through a die, and the materialundergoes decompression to atmospheric pressure so that the blowingagent separates within the body of material as it bubbles. If thetemperature is too high, there is overexpansion and the cells rupture.If the temperature is too low, there is incomplete expansion, resultingin low quality foam. In many instances, the temperature window betweenoverexpansion and underexpansion is only a few degrees Fahrenheit.

The thermoplastic elastomer closed-cell foam may contain additives, ifnecessary for a certain application of a wetsuit formed thereof. Theadditives can be provided in an amount by which the mechanical strengthand the flexibility are not affected adversely, and can include anantistatic agent, weatherability-imparting agent, UV absorber, glidant,antibacterial agent, antifungal agent, tackifier, softener, plasticizer,filler such as titanium oxide, carbon black, dry silica, wet silica,aramid fiber, mica, calcium carbonate, potassium titanate whisker, talc,barium sulfate, and the like.

Various densities of thermoplastic elastomer foam that has been expandedinto a closed-cell structure may be used to make a wetsuit of thematerial described herein. Low densities, for example, less than about0.25 grams/cubic centimeter are well suited for making the wetsuit.Other densities may also be used.

FIG. 2 illustrates a cross section of a thermoplastic elastomerclosed-cell foam 31 having a fabric covering 33. The fabric covering 33can be used to further strengthen and reinforce the thermoplasticelastomer closed-cell foam 31. In some implementations, the fabriccovering 33 is bonded to the thermoplastic elastomer closed-cell foam 31using an adhesive, a heat process, a cold process, or the like. Thefabric covering 33 can be formed of a woven polypropylene, woven nylon,aramid fiber, Lycra, spandex, or the like.

FIG. 3 illustrates a cross section of a wetsuit material 40 having athermoplastic elastomer closed-cell foam 41 and an inner liner 45. Theinner liner 45 can be used to provide added comfort to the user. In someimplementations, the inner liner 45 is bonded to the thermoplasticelastomer closed-cell foam 41 using an adhesive, a heat process, a coldprocess, or the like. In some exemplary implementations, the inner liner45 can include a fleece polypropylene, spun nylon, jersey, or a lowfriction coating such as an SCS coating, Lycra, spandex, or the like.

FIG. 4 illustrates a cross section of a wetsuit material 50 having aninner liner 55 and a fabric covering 53 applied to opposite sides of athermoplastic elastomer closed-cell foam 51. The inner liner 55 can bebonded to the thermoplastic elastomer closed-cell foam 51 using anadhesive, a heat process, a cold process, or the like. Such inner linermay be a fleece polypropylene, spun nylon, jersey, a low frictioncoating such as an SCS coating. Lycra, spandex, or the like. In asimilar fashion, the fabric covering 53 can be bonded to thethermoplastic elastomer closed-cell foam 51 using an adhesive, a heatprocess, a cold process, or the like. The fabric covering 53 may be awoven polypropylene, woven nylon, aramid fiber, Lycra, spandex, or thelike. In alternative implementations, other materials may be placed oneither side of the thermoplastic elastomer closed-cell foam 51 toenhance performance, and/or to achieve desirable characteristics of thewetsuit material 50.

FIG. 5 depicts a wetsuit 60 that is polychloroprene-free, in accordancewith implementations described herein. The wetsuit 60 can be formed ofany style and size, for example and without limitation, a short sleevedwetsuit, short john, wetsuit top, waders, or the like. The wetsuit 60can be formed of sheets of thermoplastic elastomer closed-cell foam, asdescribed above, and constructed by automated machine cutting and seambonding or hand cutting, tailoring and seam bonding. Automated or handmethods of assembly can be used to fabricated the sheets into thewetsuits 60.

In accordance with alternative implementations, the thermoplasticelastomer closed-cell foam material is cut to various patterned pieces,the pieces are joined together using a technique such as gluing ordouble gluing (glue is applied to both sides of each piece of materialto be joined together), the joined and glued together pieces mayoptionally be nipped (a technique where pressure is applied to thejoined seams), a piece of material such as heat welded tape made from amaterial such as stretch nylon is then placed on the inside of the seamand glued in place, the pieces are then blind stitched from one or bothsides, and optionally the seams are covered with a material such as heatwelded tape or the like. To complete the wetsuit 60, a zipper or zippersare added along with logos, and the like. The steps heretofore describedmay be modified or adapted to various situations, materials, and wetsuitdesigns.

A wetsuit as described above, formed of a thermoplastic elastomer (TPE)foam material, can insulate a wearer as well or better than apolychloroprene-based wetsuit. Further, the wetsuit formed of the TPEfoam material can withstand tearing, rough handling and severeconditions, yet is inherently flexible.

Although a few embodiments have been described in detail above, othermodifications are possible. Other embodiments may be within the scope ofthe following claims.

1. A wetsuit comprising: one or more sheets of closed-cell foam formedto cover one or more body parts of a wearer, the closed-cell foam beingderived from polymerized thermoplastic resin pellets mixed with at leastone foaming agent, the closed-cell foam being formed to a density ofless than 0.25 grams per cubic centimeter, each of the one or moresheets of closed-cell having a thickness between about 2 millimeters andabout 5 millimeters and enabling movement of the one or more body partsof the wearer when covered by the one or more sheets of closed-cellfoam.
 2. The wetsuit in accordance with claim 1, further comprising anouter fabric attached to and covering at least a portion of an outersurface of at least one of the one or more sheets of closed-cell foam.3. The wetsuit in accordance with claim 2, wherein the outer fabricincludes woven nylon.
 4. The wetsuit in accordance with claim 2, whereinthe outer fabric includes aramid fiber.
 5. The wetsuit in accordancewith claim 2, wherein the outer fabric includes spandex.
 6. The wetsuitin accordance with claim 2, wherein the outer fabric includes wovenpolypropylene.
 7. The wetsuit in accordance with claim 1, furthercomprising an inner liner attached to and covering at least a portion ofan inner surface of at least one of the one or more sheets ofclosed-cell foam.
 8. The wetsuit in accordance with claim 7, wherein theinner liner includes spun nylon.
 9. The wetsuit in accordance with claim7, wherein the inner liner includes polypropylene fleece.
 10. A materialcomprising closed-cell foam derived from polymerized thermoplastic resinpellets mixed with at least one foaming agent, the closed-cell foambeing formed to a density of less than 0.25 grams per cubic centimeter,each of the one or more sheets of closed-cell having a thickness betweenabout 2 millimeters and about 5 millimeters.
 11. The material inaccordance with claim 10, further comprising an outer fabric attached toand covering at least a portion of an outer surface of the closed-cellfoam.
 12. The material in accordance with claim 11, wherein the outerfabric includes woven nylon.
 13. The material in accordance with claim11, wherein the outer fabric includes aramid fiber.
 14. The material inaccordance with claim 11 wherein the outer fabric includes spandex. 15.The material in accordance with claim 11, wherein the outer fabricincludes woven polypropylene.
 16. The material in accordance with claim10, further comprising an inner liner attached to and covering at leasta portion of an inner surface of the closed-cell foam.
 17. The materialin accordance with claim 16, wherein the inner liner includes fleecepolypropylene.
 18. The material in accordance with claim 16, wherein theinner liner includes spun nylon.
 19. A method for manufacturing awetsuit, the method comprising: providing one or more sheets ofclosed-cell foam formed to cover one or more body parts of a wearer, theclosed-cell foam being derived from polymerized thermoplastic resinpellets mixed with at least one foaming agent, the closed-cell foambeing formed to a density of less than 0.25 grams per cubic centimeter,each of the one or more sheets of closed-cell having a thickness betweenabout 2 millimeters and about 5 millimeters and enabling movement of theone or more body parts of the wearer when covered by the one or moresheets of closed-cell foam; and assembling the one or more sheets ofclosed-cell foam into a pattern defining at least a portion of thewetsuit.
 20. The method in accordance with claim 19, wherein providingthe one or more sheets of the closed-cell foam includes cutting theclosed-cell foam into the one or more sheets to cover the one or morebody parts of the wearer.